In early years when the two major political parties were Federalists (Republicans) and Anti-Federalists (Democrats) I probably would've had a hard time choosing. I can relate with the Democrats not wanting a stron central government after having almost no say under a ruthless king, but i don't believe in alot of the ideals they have like slavery.
During the Republican era, I would side with the Republicans not just because they were prominent in government but because of their ideals. They believed in "free labor, free land, free men" which meant that they were against slavery and believed in free artisanship. Also, they were against plantations where only the rich could buy land and had slaves work it for them.
Now I'm a registered Republican probably because my parents and granparents are, but its also because i bleive more often in their ideals.